Swimming pool manufacture



P 1965 F, M. COLLINS ET AL 3,208,084

SWIMMING POOL MANUFACTURE Filed June 14, 1963 5 Sheets-Sheet l INVENTORJ. FORREST M. Counvs BY JAMES F? KUEHNLE jz gl f ATTYS.

Sept. 28, 1965 Filed June 14, 1965 F. M. COLLINS ETAL SWIMMING POOL MANUFACTURE 5 Sheets-Sheet 2 INVENTORS. FORREST M. CoLu/vs JAMEs F! KUEHNLE Arm.

P 1965 F. M. COLLINS ETAL 3,208,084

SWIMMING POOL MANUFACTURE Filed June 14, 1963 5 Sheets-Sheet 3 INV TORS. FORREST M. OLLINS JA M55 P. KUEH/VLE J/w M5194 Arms.

Se t. 28, 1965 F. M. COLLINS ETAL 3,208,084

SWIMMING POOL MANUFACTURE Filed June 14, 1963 5 Sheets-Sheet 4 INVENTOR. 2/ 20 Fonnesr N. Coums BYJ'AMES R KUEHNLE ATTYS.

Sept. 28, 1965 F. M. COLLINS ET AL 3,208,084

SWIMMING POOL MANUFACTURE Filed June 14, 1963 5 Sheets$heet 5 INVENTOR, FORREST M COLL/NS BYL/AMES' P KUEHNLE ATTvs.

United States Patent 3,208,084 SWD/IMHNG POOL MANUFACTURE Forrest M. Collins, Colville, and James P. Kuehnle, Spokane, Wash, assignors to Holiday Pools, Inc., Spokane, Wash.

Filed June 14, 1963, Ser. No. 287,822 3 Claims. (Cl. 4-172) This invention relates to a novel method of constructing a prefabricated swimming pool and also to the product obtained thereby. The pool is primarily adapted for use in above ground installations, such as indoor swimming pools, roof top swimming pools, and similar installations, wherein the full surface support normally afforded by ground level installations is unavailable.

It is a first object of this invention to provide a novel method of constructing a swimming pool having inner and outer shells manufactured entirely of resin and glass fiber which have sufiicient stability and strength to support the water volume which must be contained therein without complete surface support from the building framework. According to the present method one can construct a pool with inner and outer glass fiber reenforced shells having a resin laminate or binding agent, the two shells being stiffened by a light weight core material, such as resin impregnated paperboard honeycomb.

It is another object of this invention to provide such a method whereby conventional honeycomb reenforcing can be applied to the Surfaces of a swimming pool, establishing a final product having a continuous inner shell and a. continuous outer shell spaced from the inner shell, the two being in a unit construction.

Another object of this invention is to provide a swimming pool for roof top or indoor installations which is completely sealed and which requires no surfaces maintenance either on the interior or exterior surfaces thereof. By providing a glass fiber and resin construction, maintenance costs of this pool are reduced to an absolute minimum.

Another object of this invention is to provide a prefabricated swimming pool which will provide insulating qualities not previously obtainable in prior swimming pool constructions. This is particularly important in locations where the water of a pool must be heated in order to lengthen the swimming season.

Another object of this invention is to provide a swimming pool having walls which will effectively deaden sounds in the pool, such as the vibrations caused by use of a diving board. This feature is of importance in indoor and roof top applications on buildings such as motels or hotels.

Another object of this invention is to provide a swimming pool requiring a minimum of structural support from the building framework upon which it is mounted. By saving on framing costs, the instant pool can justify the increased cost of its double shell and reenforcing core.

One final object of the invention is to provide a roof top pool which is light weight in construction, averaging between 40 to 60 percent of the weight of a comparable concrete pool when filled with water.

These and further objects will be evident from a study of the following disclosure which relates to a particular method and resulting pool. It is to be understood that this description is merely by way of example, and that the invention disclosed herein is not to be restricted or limited except as set out in the claims which follow the detailed specification.

In the drawings:

FIGURE 1 is a top view looking down on an installed pool constructed according to the following specification;

FIGURE 2 is a sectional view taken along line 2-2 in FIGURE 1;

3293,84 Patented Sept. 28, 1965 ice FIGURE 3 is an enlarged sectional View taken along line 33 in FIGURE 1;

FIGURE 4 is an enlarged sectional view taken along line 4-4 in FIGURE 1;

FIGURE 5 is an end view of the installed pool as seen from the left hand end of FIGURE 1;

FIGURE 6 is an end view of the installed pool as seen from the right hand end of FIGURE 1;

FIGURE 7 is a fragmentary perspective view showing the various layers of materials used in the fabrication of a pool wall according to this invention.

FIGURE 8 is an enlarged sectional view taken along line 8-8 in FIGURE 1;

FIGURE 9 is a longitudinal sectional view taken through the center of a pool prior to its removal from mold on which it is formed; and

FIGURE 10 is a typical sectional view through a reenforced wall of the pool, showing the construction thereof.

This invention is concerned with the manufacture of a swimming pool, particularly a swimming pool designed for roof top installations on buildings such as motels, hotels, apartments and similar structures. Most pools of such installations are made of metals such as steel or aluminum or concrete poured in place. Metals pose practical problems of fabrication, cost and maintenance. Concrete pools require a great deal of structural framework merely to support their own weight. Concrete pools have a common difliculty due to their rigidity and due to the fact that almost every pool eventually seeps water or leaks. The present invention contemplates a one pi e prefabricated pool which can be mounted on a building, and which has a greatly lessened total weight. Savings in total cost are effected by reducing the cost and size of the structural members necessary to support it.

A pool constructed according to the present invention basically comprises an inner shell 10 and an outer shell 11, each of which comprise laminations of glass fibers in a resin laminate. The pool structure is molded over a mold 12 which has an outer surface configuration complementary to the desired inside surface configuration of the finished pool. A longitudinal sectional view of the mold 12 is shown in FIGURE 9.

The pool construct-ion involves several steps which proceed to build the inner and outer shells 10 and 1 1, and which include the application of a reenforcing core material 13, which is preferably of the honeycomb construction illustrated generally in FIGURE 7. This honeycomb construction is commercially available and is manufactured in sheets from various materials. In actual use, the honeycomb construction utilized according to this invention has been made of paperboard impregnated with phenolic resin.

In preparation for the laminating of a pool, the outer surfaces of the mold 12 are coated with a parting agent of conventional choice, or are finished so as to allow the release of resins poured thereon. A continuous gel coat 14 is then applied to the mold 12 by means of a spray apparatus capable of handling the rather thick liquid resin. The gel coat 14 can be of any desired thickness and can be colored, transparent, or translucent. The gel coat 14 in actual use will be of a thickness between and 6 inch.

The gel coat 14 is allowed to thicken on the mold 12 due to the action of the catalyzing agents mixed therein, and can be allowed to completely harden before the next step is taken. In any event, the gel coat will normally be allowed to gel to a point where the outer surface thereof assumes a tacky state.

The gel coat 14 is then covered by a layer of glass fiber cloth 15 which is tightly woven of glass fiber strands. In preparing the inner shell 10, it is import-ant that the thickness of the inner shell be constant over the entire surface area of the pool, for reasons which will become evident below. Therefore it is necessary that all joints in the cloth layer be scarf joints. The cloth layer 15 is thoroughly impregnated with polyester resin and is thereby secured to the outer surface of the gel coat 14.

To further reenforce the inner shell 10, several alternating layers of glass fiber mat and roving are then applied in succession over the cloth layer 15. The layers of mat are merely sheets of pressed fibers located in random directions. The glass fiber roving 18 is a more loosely woven structure having wider strands of glass fibers. Each layer of mat or roving generally shown as a group in FIGURE 7 and denoted as 16, is thoroughly impregnated with liquid polyester resin so that the layers 16 and the cloth layer 15, as well as the gel coat 14, become an integral unit when the inner shell 10 has been allowed to cure.

In actual practice, for pools having a length of approximately 35 feet, the inner shell 10 is comprised of a single layer of cloth '15 and three laminations of mats and two lamination-s of roving. This number can be varied, depending upon the size of the pool being manufactured, and available supporting framework for the finished pool.

In the preparation of the innel shell 10, the first four layers are applied in general succession and are allowed ,to gel to a hardened state. All joints between adjacent layers 16 are scarf joints and the joints in one layer are ofi set from those in the next layer. In this way the maximum amount of strength is assumed in a construction having a constant thickness. After the partly finished inner shell 10 has hardened, the outer surface thereof is sanded and finished to a smooth condition so that it will provide the suitable flat surface for the application of the core material 13. Although honeycomb materials are being introduced that are flexible, most available core material of this type is rigid and is manufactured with very exacting fiat surfaces. This is the primary reason for the careful scrutiny of the inner shell layers, and for the finishing of the next to the last layer of mat 16 prior to the completion of the pool structure.

Before being applied to the pool structure, the honeycomb sheets used as the core material 13 are coated on one side with a layer of glass fiber mat 17 which is allowed to harden in its matrix of polyester resin while resting upon a flat sheet of Waxed paper on a smooth flat surface. This seals one end of each honeycomb cell, and provides a more stable backing element for the handling of the honeycomb core material 13.

After the single layer of mat 17 has cured on the honeycomb core material 13, a final layer of saturated mat 16 is added to the inner shell 10 as each block of honeycomb core material is applied thereto. The wet mat layer 16 is pressed against the outside of the inner shell 10 and the open surface of the honeycomb core material 13 is then pressed into the mat layer 16 and is held under pressure until the resin has gelled. As each section of the honeycomb co're material 13 is applied to the wet mat layer 16, the layer is wrapped around the edges of the mat, thereby sealing each section from the others. The adjacent section of honeycomb core material 13 is then pressed upon another mat layer 16 and is urged laterally against the adjacent section of honeycomb core material 13, which is separated therefrom by the folded portion of the layer 16. This construction provides a strong cohesive junction between adjacent sections of the honeycomb core material 13, and seals both the axial and lateral edges of each section of honeycomb core material 13. The core material 13 is held in place by the polyester resin, so that the entire structure will cure as a unit, producing a structure much stronger than would be the case were an adhesive to be used.

With the conventional honeycomb core material 13 available today, sharp corners cannot be covered due to its inherent rigidity. It has been found that the reenforcing of the larger fiat pool surfaces is sutficient to provide the necessary stability and strength in a pool, and therefore the sharp corners with the usual increased strength in a radius, need not be reenforced in the above manner. It is also true that the many fittings necessary in a swimming pool should be mounted through a solid section of wall, rather than through the portions which are reenforced by the honeycomb core material 13. For this reason, areas in which the fittings are to be mounted are not coated with the core material 13, but are built up with additional laminations extended from both sides of the outer shell 11.

The pool construction is completed by the fabrication of the outer shell 11. Again using a series of five laminations, four additional layers must be added to the mat layer 17 which was previously cured prior to application of the core material 13 on the inner shell 10. The five layers include the previously described mat layer 17 and alternating layers of mat and roving 17 which form a continuous shell over both the honeycomb core material 13 and the exposed surfaces of the inner shell 10. These layers are applied in succession, and are amply saturated with polyester resin to provide solid laminae. The final lamiantion consists of a layer of glass fiber roving applied over the entire outer surface of the shell 11. This final layer is also saturated with polyester resin, and the entire unit is then allowed to cure.

The outer surface n the outer shell 11 can be painted or decorated as might be desired, since the above construction provides a pool which cannot leak and which can be incorporated in usable storage space in a building such as a motel. Decoration might be applied to the pool surface, so that the pool itself could be fitted into the decorative scheme of an interior room. Various unusual lighting effects can be obtained by either lighting the interior or the exterior of the pool, and by making use of the shadowy honeycomb pattern built into the structure.

After the pool has been allowed to completely cure, it is removed by freeing it from mold 12, the initial release being obtained by air pressure directed to shell 10 through small apertures 19 in mold 12. The pool is then ready for installation in or on a building.

The resins used in the fabrication of the shells 10, 11 and in the bonding of core material 13 can be chosen from many available types. For best strength, resiliency and economy, a resilient polyester resin has been used to date. The following are exemplary formulas for both the gel coat and the lamin'ations, using two polyester resins made and sold by Allied Chemicals.

Gel Coat Percent Polyester resin 73 (Allied Chemical PE 213) Cobalt naphthanate (6% solution) 3 MEK peroxide 2 /2 Inert clay filler 10 Cabisil 3 Titanium oxide 5 Thalo green .25

Cabisil is a silicon filler sold by Cabot Chemicals. Titanium oxide provides an opaque white color, tinted green by the Thalo green.

Laminating resin Percent Polyester resin 94 /2 (Allied Chemicals PE405) Cobalt naphthanate (6% solution) 3 MEK peroxide 2 /2 The gel coat has an approximate gel time of 1 /2 hours, while the laminating resin mix has a gel time of about 20 minutes.

For this application, high strength is an absolute necessity. This is achieved by using high density laminations comprising 45-55% glass fiber by weight. The exceptions are the two bonding laminates immediately adjacent to the two edges of the core material 13, which will run 25-35% glass fiber so as to provide excess resin to perfect the necessary seals.

FIGURES 1 through 6 show a typical pool installastion. The pool is first lifted onto a cradle generally designated :by the numeral 20. The cradle 20 is composed of structural members such as steel I-beams which are fabricated in a configuration complementary to the lower pool surfaces. The longitudinal primary girders 21 are supported by the building frame (not shown). Mounted across the girders 21 are transverse beams 22 which fit along the bottom of the outer shell 11. Extending upwardly from the ends of the beams 22 are vertical beams 23 which are capped by supporting channels 24 that support the safety ledge 25 along the intermediate portions of the pool walls adjacent the deeper or diving end thereof. The entire pool might be suspended from supporting members along the ledge 25 were such a support desirable in a particular instance.

The pool is lowered into place on corner blocks, and the slight separation between the pool and the supporting members is caulked with the same polyester resin used in the lamination of the shells with additional filler, thereby providing an effective seal and adhesive between the body of the pool and the supporting beams. The sections of the pool structure which were fabricated without core material 13 are then cut to receive the various fittings shown generally by the numeral 26. The decking 27 adjacent to the pool can be poured of concrete material or prefabricated material can be used, preferably interlocking with the downwardly turned edge 28 formed along the upper perimeter of the pool. This concrete decking 27 rovides positive lateral support for the top edges of the pool and insure proper stability :of the pool structure. The entire weight of the pool, however, is carried by the lower beam members described above.

The pool is then ready for use, and can be filled with water to the normal depth. A pool having top dimensions of 15 feet by 35 feet and a maximum depth of 8 feet will weight about 8,000 lbs. when empty and about 150,000 lbs. when filled. The same ool made of concrete, would weigh between 125,000 to 150,000 lbs. when empty, plus the additional weight of heavier beams necessary for its support. This considerable saving in weight accounts for a definite economy in the fabrication of the pool described herein and allows the supporting structure to be made much more economically. It also allows for installation on existing supports not adequate to handle a concrete pool. The fact that the pool can be prefabricated off the site reduces the labor and confusion involved in a typical installation.

The pool manufactured by the above method has many substantial advantages over conventional pools. The use of glass fiber reenforced structures produces a pool that requires no surface maintenance, and introduces amazing stability and strength in such a light weight structure. Actual deflection in the walls of a typical pool is almost unnoticeable, and well within the limitations of the material. The walls are sufficiently resilient to allow expansion or contraction due to changes in temperature and load variations that might be caused by variances in the water level. The water within the pool can be maintained indefinitely, and can be allowed to freeze without danger of cracking the pool surfaces.

A very definite advantage is gained by the fact that the entire pool wall is continuous, so that the pool cannot leak. A pool might be made in joined sections where dictated by size or access, with the same general results.

Another advantage is that the honeycomb core material 13 acts as an insulator by capturing a dead air space between the inner and outer shells and 11. This is of particular importance in areas where the water within the pool must be heated in order to allow one to utilize the pool. The insulating effect afforded by the core material 13 prevents condensation of water on the outer surface of the shell 11 due to variances in temperature between the water and the outside air. This allows one to utilize the surrounding room without worry concerning condensation. The dead air space between the shells 10 and 11 also minimizes the transmission of sounds from the interior of the pool to the area surrounding the outer shell 11. A very common complaint in roof top pools is the sound caused by the bouncing of diving boards. It has been found that this sound is effectively damped by used of the present construction.

Other core materials suitable for this construction are expanded foam resins, such as Styrofoam, polyethylene or polyurethanes.

Various modifications might be made in the above method and product without deviating from the intended scope of this invention. The pool configuration could be modified to meet the many different applications and yet the basic method and product would remain the same. Various thicknesses of honeycomb core material 13 might be used, in fact, the actual constructions used to date have used thickness of one inch along the upper walls and thicknesses of two inches around the lower surfaces. These features are not critical to the practice of the invention which basically envisions the use of a double shelled pool wall with an interior reenforcing core material. For these reasons onlly the following claims are asserted as limited definitions of the invention.

Having thus described our invention, we claim:

1. A prefabricated swimming pool, comprising:

a smooth surface gel coat formed at the inside surface of an inner ool shell and reenforced by successive backing layers of reenforcing fiber impregnated and bonded to one another in a resin laminate;

a honeycomb reenforcing material bonded to the outer surfaces of the inner shell, the honeycomb reenforcing material being discontinued at corners and over areas adapted to receive pool fittings;

and an outer shell formed continuously over the honeycomb ree-nforcing material and inner shell, said outer shell being composed of successive layers of reenforcing fiber impregnated and bonded in a resin laminate and sealed along its entire surface area to the exposed surfaces of said honeycomb reenforcing material and innner shell.

2. A prefabricated swimming pool, comprising:

a smooth surfaced gel coat formed at the inside surface of an inner pool shell and reenforced by successive backing layers of reenforcing fiber impregnated and bonded to one another in a resin laminate;

a honeycomb reenforcing material bonded in sheets placed side by side on the outer surfaces of the inner shell, the outside layer of fiber and resin of said inner shell being folded outwardly over each edge of a single honeycomb sheet in sealing relationship thereto, adjacent sheets of honeycomb material being in sealed contact with the folded portions of said outside layer;

and an outer shell formed continuously over the honeycomb reenforcing material and inner shell, said outer shell being composed of successive layers of reenforcing fiber impregnated and bonded in a resin laminate and sealed along its entire surface area to the exposed surfaces of said honeycomb reenforcing material and inner shell.

3. A prefabricated swimming pool, comprising:

a smooth surfaced gel coat formed at the inside surface of an inner pool shell and reinforced by successive backing layers of reinforcing fiber impregnated and bonded to one another in a resin laminate;

a light weight core reinforcing material bonded to the outer surface of the inner shell over the pool surface areas;

and an outer shell covering the core reinforcing ma- 7 terial and said innner shell comprised of successive layers of reinforcing fiber impregnated and bonded in a resin laminate;

.said core material comprising a honeycomb laminate,

the honeycomb apertures being oriented perpendicularly to the pool surfaces and being sealed respectively by the resin laminate of said inner and outer shells.

References Cited by the Examiner UNITED STATES PATENTS 12/54 Strand 4-173 Gagne et al. 4-172 Merriman 161-68 Friedlander et a1. 4-172 Johnston 156-212 Long 4-173 Randall et a1. 161-69 Nordberg et a1 161-68 Bosch 161-68 10 LAVERNE D. GEIGER, Primary Examiner.

SAMUEL ROTHBERG, LAVERNE D. GEIGER,

Examiners. 

3. A PREFABRICATED SWIMMING POOL, COMPRISING: A SMOOTH SURFACED GEL COAT FORMED AT THE INSIDE SURFACE OF AN INNER POOL SHELL AND REINFORCED BY SUCCESSIVE BACKING LAYERS OF REINFORCING FIBER IMPREGNATED AND BONDED TO ONE ANOTHER IN A RESIN LAMINATE; A LIGHT WEIGHT CORE REINFORCING MATERIAL BONDED TO THE OUTER SURFACE OF THE INNER SHELL OVER THE POOL SURFACE AREAS; AND AN OUTER SHELL COVERING THE CORE REINFORCING MATERIAL AND SAID INNER SHELL COMPRISED OF SUCCESSIVE LAYERS OF REINFORCING FIBER IMPREGNATED AND BONDED IN A RESIN LAMINATE; SAID CORE MATERIAL COMPRISING A HONEYCOMB LAMINATE, THE HONEYCOMB APERTURES BEING ORIENTED PERPENDICULARLY TO THE POOL SURFACES AND BEING SEALED RESPECTIVELY BY THE RESIN LAMINATE OF SAID INNER AND OUTER SHELLS. 